Controlling microbial growth in noncarbonated dilute juice beverages is an ongoing concern among beverage manufacturers. Such beverage products, when exposed to food spoilage microorganisms, provide an excellent environment for rapid microbial growth. Such exposure can, and infrequently does, result from accidental inoculation of the beverage products during manufacturing or packaging. Food spoilage microorganisms can then rapidly proliferate by feeding on nutrients provided by the fruit juice component of the noncarbonated dilute juice beverages.
Of course, microbial proliferation in noncarbonated dilute juice beverages will not occur without the requisite product exposure to yeast or bacteria. Manufacturing and packaging operations directed to the prevention of such exposure is preferred, but provisions are often made for any infrequent accidental exposure to the isolated beverage product. Such provisions are directed to limiting or preventing subsequent microbial proliferation to thus limit or prevent food spoilage.
Microbial stability of dilute juice beverage products can be provided to some extent by heat pasteurizing during packaging (hot packing) or by packaging under completely aseptic conditions (aseptic packaging). Hot packing involves pasteurization of the beverage and its container such that the resulting sealed beverage product contains no food spoilage microorganism. Likewise, aseptic processing and packaging of a pasteurized beverage will produce a beverage product completely free of food spoilage microorganisms. Accordingly, these beverage products are extremely shelf stable since there are assuredly no food spoilage microorganisms therein to feed on the beverage nutrients and rapidly proliferate.
Aseptic packaging methods, however, are often unsuitable for manufacturing beverages products packaged in certain beverage containers, e.g., rigid containers such as glass, plastic and cans. An aseptic or sterile environment is difficult to maintain during aseptic packaging operations. Frequent cleaning of the packaging line is necessary which is time consuming and expensive.
Hot packing methods are likewise unsuitable for manufacturing certain types of beverage products. This well known method involves heat pasteurization of the juice beverage during packaging at temperatures of between about 85.degree.-105.degree. C. This method is commonly utilized in the manufacture of canned or bottled (glass) beverages. However, not all beverage containers can withstand heat-pasteurization during packaging. For example, flexible containers made from high density polyethylene, which have become more popular with consumers, should not be subjected to the pasteurization temperatures utilized during hot packing operations.
Preservatives have been used in noncarbonated dilute juice beverages to provide some degree of microbial inhibition. Preservatives commonly used in beverage products include, for example, sorbates, benzoates, organic acids, and combinations thereof. However, such preservatives often contribute an off-flavor to the beverage products when used at the levels necessary to inhibit subsequent microbial proliferation during storage. Moreover, when used at concentrations sufficiently low to avoid off-flavor development, such preservatives have heretofore been unable to effectively inhibit the growth of many preservative resistant spoilage microorganisms.
Accordingly, most noncarbonated dilute juice beverages are hot packed in cans or glass bottles or aseptically packaged.
The foregoing considerations involving the effective inhibition of subsequent microbial proliferation in noncarbonated dilute juice beverage products indicates that there is a continuing need to identify noncarbonated dilute juice beverage products that can be manufactured without the use of hot packing or aseptic packing operations, and that are shelf stable for a reasonable amount of time without the use of excessive concentrations of preservatives. It has previously been discovered that certain chilled noncarbonated dilute juice beverage products could be maintained at ambient temperatures for at least about 10 days, preferably for at least about 20 days, without substantial microbial proliferation therein.
Such chilled noncarbonated beverage products include from about 400 ppm to about 1000 ppm of a preservative selected from the group consisting of sorbic acid, benzoic acid, alkali metal salts thereof and mixtures thereof; from about 0.1% to about 10% by weight of fruit juice; and from about 900 ppm to about 3000 ppm of a polyphosphate having the formula ##STR1## where n averages from about 3 to about 100, preferably from about 13 to about 16, and each M is independently selected from the group of sodium and potassium atoms. The noncarbonated beverage products further comprise from about 80% to about 99% added water by weight of the beverage products, wherein the added water contains from 0 ppm to about 60 ppm of hardness, and preferably from 0 ppm to about 300 ppm of alkalinity. The noncarbonated beverage products have a pH of from about 2.5 to about 4.5 and an ambient display time of at least about 10 days.
Unfortunately, these chilled noncarbonated beverages do not necessarily provide microbial stability at ambient temperature when the added water component of these beverages has a hardness of more than about 60 ppm. Since water supplies used for preparing these noncarbonated beverages frequently have a hardness of well above 60 ppm, it is often necessary to treat or "soften" the water before it can be incorporated into the beverages hereinbefore described.
Conventional methods for softening water can be very expensive. Moreover, it is not always possible or convenient to soften water to less than about 60 ppm using conventional techniques. For example, one conventional method for softening water involves treating the water with Ca(OH).sub.2. This well known method is most suitable and economical for water having an initial hardness of 100 to 150 ppm as calcium carbonate. However, it is not uncommon for water sources to have a hardness in excess of 150 ppm. Another conventional method for softening water involves ion-exchange operations. This method, however, is preferably used to soften water having an initial hardness of 50-100 ppm.
Due to the costs associated with softening of water and to limitations in the methods themselves, it is an object of the present invention to provide noncarbonated beverages having microbial stability at least equal to that of previous noncarbonated beverages, but wherein the added water component can comprise water having a hardness in excess of 60 ppm to avoid the cost and difficulties associated with having to soften the water to a level below 60 ppm first. It is a further object of the present invention to increase the microbial stability of the beverages of the present invention compared to prior beverages.